Department of Chemistry, 62 Talbot Avenue, Tufts University , Medford, Massachusetts 02155, United States.
Department of Biomedical Engineering, 4 Colby Street, Tufts University , Medford, Massachusetts 02155, United States.
Langmuir. 2017 Oct 17;33(41):10877-10885. doi: 10.1021/acs.langmuir.7b01469. Epub 2017 Oct 2.
This paper describes polyelectrolyte multilayer films prepared by the layer-by-layer (LbL) technique capable of undergoing dissolution upon exposure to either ultraviolet or near-infrared light. Film dissolution is driven by photochemical deprotection of a random methacrylic copolymer with two types of side chains: (i) 6-bromo-7-hydroxycoumarinyl esters, photocleavable groups that are known to have substantial two-photon photolysis cross sections, and (ii) cationic residues from the commercially available monomer N,N-dimethylaminoethyl methacrylate (DMAEMA). In addition, the dependence of stability of both unirradiated and irradiated films on pH provides experimental evidence for the necessity of disrupting both ion-pairing and hydrophobic interactions between polyelectrolytes to realize film dissolution. This work therefore provides both new fundamental insight regarding photolabile LbL films and expands their applied capabilities to nonlinear photochemical processes.
本文描述了通过层层（LbL）技术制备的聚电解质多层膜，这些膜在暴露于紫外光或近红外光下能够溶解。膜的溶解是由具有两种侧链的无规甲基丙烯酸酯共聚物的光化学保护基团的脱保护驱动的：（i） 6-溴-7-羟基香豆素酯，已知具有很大的双光子光解截面，以及（ii） 商业上可获得的单体 N,N-二甲基氨基乙基甲基丙烯酸酯（DMAEMA）的阳离子残基。此外，未辐照和辐照薄膜稳定性对 pH 的依赖性为破坏聚电解质之间的离子配对和疏水相互作用以实现薄膜溶解提供了实验证据。因此，这项工作不仅为光不稳定的 LbL 薄膜提供了新的基本见解，而且还扩展了它们在非线性光化学过程中的应用能力。
